The present invention relates to an apparatus and a method for sterilising containers, and in particular to a method and an apparatus for sterilising containers by means of electron beams.
In the beverage-producing industry, it is known firstly to form plastic containers and then to fill said containers with a beverage. It is sometimes necessary for these containers to be sterilised, particularly on the inner sides thereof, prior to being filled. One method widely used in the prior art is sterilisation by means of sterilising gases and in particular by means of hydrogen peroxide. More recently, however, efforts are being made to reduce the use of chemicals when sterilising containers. Recently, therefore, apparatuses and methods have also become known which sterilise the containers by other measures, such as by means of ultraviolet radiation or electron beams for example.
In the as yet unpublished European patent application no. 07 007 977.7 by the Applicant, a method and an apparatus have been described in which emitting fingers, which emit the electron beams, are introduced into a container and the container is displaced relative to this emitting finger in the longitudinal direction of the container for the purposes of sterilisation. With this procedure, an efficient sterilisation of the interior of plastic containers is possible. However, it must nevertheless be noted that the containers cannot be acted upon by radiation in any random manner for the purposes of sterilisation, but rather this radiation must be subject to both maximum and minimum limit values with regard to its intensity. The minimum values are determined by the dose necessary to achieve efficient sterilisation of the containers, which in turn depends on many factors, for example on the germs to be killed. The maximum dose is limited by the fact that no damage should occur on the container to be sterilised.
The object of the present invention is therefore to provide a method and an apparatus which allows a more accurate dosing of the radiation intensities applied to containers. The sterilisation of containers by means of radiation is also intended to be improved.